Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the safety profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false), so the bar is lower. The description still earns credit by disclosing the non-obvious replacement semantics of `events` ('replaces the whole list rather than adding to it'), a behavioral trait not derivable from the schema. It does not state whether omitted fields are left unchanged, which is the one remaining gap.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences with zero waste; the core purpose is front-loaded and the important caveat follows immediately. Every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutation tool with no output schema, the description covers the main fields and the tricky events behavior, but omits the critical update semantic of what happens to fields that are not passed (all params are nullable with null defaults). An agent cannot tell from the definition whether omitting a field preserves or clears it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 20% (only webhook_id is documented), so the description must compensate. It names three of the four optional fields (url, events, is_active) and clarifies the replace semantics of events, but ignores `name` and gives no indication of what null/default values do for omitted fields.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Update') and resource ('a webhook') and enumerates the mutable fields (URL, events, active state). It is clearly distinguishable from create_webhook, delete_webhook, and get_webhook, though it does not name any sibling explicitly and omits the 'name' field from the list.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this tool versus alternatives such as create_webhook or the block/project update tools. Usage is only implied by the verb, and no prerequisites (e.g. needing a webhook_id from list_webhooks) are stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.